Track ball



FIG. 1 is a perspective view of a track ball showing my design;

FIG. 2 is a front perspective view thereof;

FIG. 3 is a rear perspective view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right rear perspective view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof. 

The ornamental design for a track ball, as shown and described. 